Julie O'Neill was secretary general at the department from 2002 to 2009 and was there when Aer Lingus floated on the stockmarket in 2006.

She worked in eight government departments during a 37-year career as a civil servant and is currently working as an independent management consultant.

The no-frills airline has also tapped Louise Phelan, the vice president of global operations EMEA at Paypal, the business owned by Ebay.

Earlier this year Ms Phelan helped to secure 1,000 new jobs for a Paypal operation in Dundalk. The company already employs about 1,500 people in Dublin.

In London, meanwhile, the courts rejected Ryanair's efforts to block a UK Competition Commission probe of its 30pc stake in Aer Lingus.

The Court of Appeal said there was no reason why the commission shouldn't be able to undertake the investigation even though the European Commission (EC) is also currently examining whether Ryanair should be permitted to buy Aer Lingus outright.

"There can be no doubt that a stay of the Competition Commission's investigation at the present time is neither necessary nor appropriate pending the conclusion of the EC's consideration of the public bid," said the Court of Appeal in its decision.

Ryanair – which launched a €694m offer to buy Aer Lingus this summer – said it has immediately instructed its lawyers to refer the matter to the UK's Supreme Court.

Court of Appeal

The airline pointed out that the Court of Appeal had ruled in May that the UK's Office of Fair Trading was prevented from investigating Ryanair's stake in Aer Lingus while the outcomes of appeals related to the European Commission's previous decision to block Ryanair's 2006 offer to buy its smaller rival were awaited.

But the Court of Appeals said yesterday that those Ryanair and Office of Fair Trading proceedings were "materially different" from the present case.

The court added: "Whatever the EC decides, or any court on appeal from the EU decision holds, the UK has exclusive jurisdiction to consider the competition implications of Ryanair's minority shareholding."

It also said that even if the Competition Commission was to eventually rule that anti-competitive issues arose and suggested remedial action, then that remedial action could be deferred until the results of the EC's investigation were published.

The court added that the Competition Commission could also at that point reconsider its proposed remedial action based on the EC decision and the associated reasoning. Remedial action could include forcing Ryanair to sell its Aer Lingus stake.

Aer Lingus chairman Colm Barrington welcomed the ruling. He said the decision is a "key milestone" on the path towards Ryanair being forced to sell its stake in its smaller rival.